BS 6651:1992

Committees responsible
Foreword
Code of practice
Section one. General
0 Introduction
1 Scope
2 Definitions and abbreviations
3 Technical aspects of lightning
4 Effects of a lightning strike
5 Function of a lightning conductor
6 Materials
7 Dimensions
Section two. Basic considerations
8 General
9 Need for protection
10 Zone of protection
Section three. System design
11 General considerations
12 Consultation
13 Component parts
14 Air terminations
15 Down conductors
16 Earth termination network
17 Earth electrodes
18 Metal in or on a structure
19 Structures exceeding 20 m in height
20 Structures with roofs of high flammability
21 Buildings with explosive or highly flammable
    contents
22 Dwelling houses
23 Fences
24 Trees and structures near trees
25 Structures with radio and television aerials
26 Miscellaneous structures
27 Corrosion
Section four. Construction sites
28 Structures
29 Overhead power lines
Section five. Inspection, testing and records
30 Inspection
31 Testing
32 Records
Section six. Maintenance
33 Maintenance and upkeep
Appendices
A Explanatory notes on some of the recommendations of
    this code
B Guidance on the application of BS 6651
C General advice on protection of electronic
    equipment within or on structures against lightning
Tables
1 Recommended fixing centres for conductors
2 Recommended materials for the manufacture of
    lightning protection components
3 Some characteristics of typical materials listed in
    table 2
4 Minimum dimensions of component parts
5 Minimum thicknesses of sheet metal used for roofing
    and forming part of the air termination network
6 Relationship between thunderstorm days per year and
    lightning flashes per km2 per year
7 Comparative probability of death for an individual
    per year of exposure
8 Weighting factor A (use of structure)
9 Weighting factor B (type of construction)
10 Weighting factor C (contents or consequential
    effects)
11 Weighting factor D (degree of isolation)
12 Weighting factor E (type of terrain)
13 Examples of calculations for evaluating the need for
    protection
14 Relationship between diameter and mass of electrodes
15 Effective collection area of mains services
16 Effective collection area of data lines
17 Weighting factor F (type of construction)
18 Weighting factor G (degree of isolation)
19 Weighting factor H (type of terrain)
20 Classification of structures and contents
21 Classification of exposure level
22 Location category A (mains)
23 Location category B (mains)
24 Location category C (mains)
25 Location category C (data lines)
26 Definitions of the waveshape parameters 1.2/50
    micro seconds
Figures
1 Number of lightning flashes to the ground per km2
    per year for the UK
2 Typical dsigns for the lightning conductor fixings
3 Map showing thunderstorn days per year throughout
    the world
4 Details of structures and collection areas
5 Examples of lightning protection systems for brick
    chimneys
6 Protective angles and zones of protection for
    various forms of air termination
7 Examples of air terminations and down conductors
    using handrails, metal copings and reinforcing bars
8 Test joints
9 Typical forms of vertical air terminations
10 Air terminations for a flat roof
11 Air terminations for flat roofs at different levels
12 Air terminations for large areas of roof of various
    profiles
13 Air terminations and concealed conductors for
    buildings less than 20 m high with sloping roofs
14 Air terminations and down conductors for flat roof
    buildings where the air termination conductors have
    a PVC oversheath
15 Air terminations for tall conducting structures
16 Air termination network with horizontal conductors
    for structure with explosive or highly flammable
    contents
17 Air termination for a flat roof showing connection
    to standing seam joint when a metallic roof is used
    as a part of the air termination network
18 Air termination and zone of protection for simple
    structure with explosive or highly flammable
    contents
19 Patterns of down conductors (natural or not) for
    various forms of tall building
20 Voltage gradients along ground surface near to
    masts, towers and columns with single and multiple
    earth electrodes (see 15.2 and A.1.2)
21 Down conductor in internal duct
22 Re-entrant loops
23 Lightning protection system for tall buildings (over
    20 m high) showing air terminations, down conductors
    and bonds to projections above roof
24 Example of an earth electrode seal for use within a
    tanked structure
25 Earth terminations: arrangement of rod earth
    electrodes
26 Curve for determining the probable maximum current
    in the lightning flash from the ratio P/Po
27 Transfer inductance in simple loop
28 Curve for determination of the flashover voltage in
    air as a function of spacing
29 Plan of collection area
30 Diagram showing bonding to services (gas, water and
    electricity)
31 Church towers and spires
32 Air termination with twin suspended horizontal
    conductors and zone of protection for structure with
    explosive or highly flammable contents
33 Vertical air termination for protection of
    explosives stores
34 Exceptional protection against overvoltages induced
    by lightning in incoming supplies to buildings with
    explosive or highly flammable contents
35 Lightning protection for domestic properties
36 Lightning protection for tents
37 Lightning protection (low cost installation) for
    isolated farm buildings of brick and tile
    construction
38 Lightning protection system for sports stadium
    (football ground)
39 Typical arrangement for protection of windmills
40 Bridges
41 Example of use of Rolling Sphere method for
    assessing a tall complex building for regions
    where air terminations are needed
42 Strike location points to industrial installations
    which could affect electronic systems
43 Configurations involving electronic equipment
44 Lightning current distribution in a fifteen
    stanchion building
45 Plan view of fifteen stanchion building showing
    resulting field line plot (transfer inductance
    contours) for a lightning pulse
46 Collection area of structure and adjacent associated
    structure
47 Cables entering a building separated from a
    transmitter mast
48 Bonding of cables and pipes at entry and exit to
    buildings
49 Methods of reducing induced voltages
50 Hybrid earth system applied to equipment in multi-
    floor building
51 Earth connection from zero voltage reference of
    equipment to earth of surge protection devices
52 Direct injection into exposed electrical systems
53 Protection from direct injection
54 Protection of cables located alongside tall vessels
    and bonding at roof level
55 Locations where high, medium or low lightning
    current can be expected to flow through cables
    associated with a reaction vessel
56 Lightning current characteristics for severe
    negative ground strike
57 Strike points on plant
58 Inductance
59 Simplified circuit diagram of the combination wave
    generator
60 Waveshape of short circuit current (1.2/50 micro
    seconds)
61 Waveshape of short circuit current (8/20 micro
    seconds)

Gives guidance on risk assessment and installation of lightning protection systems. General advice is also given on protection against lightning of electrical/electronic equipment within or on structures.